| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hdfs.server.namenode.ha; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.net.URI; |
| import java.util.List; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.hdfs.client.HdfsClientConfigKeys; |
| import org.apache.hadoop.ipc.RPC; |
| |
| /** |
| * A FailoverProxyProvider implementation which allows one to configure |
| * multiple URIs to connect to during fail-over. A random configured address is |
| * tried first, and on a fail-over event the other addresses are tried |
| * sequentially in a random order. |
| */ |
| public class ConfiguredFailoverProxyProvider<T> extends |
| AbstractNNFailoverProxyProvider<T> { |
| |
| protected final List<NNProxyInfo<T>> proxies; |
| |
| private int currentProxyIndex = 0; |
| |
| public ConfiguredFailoverProxyProvider(Configuration conf, URI uri, |
| Class<T> xface, HAProxyFactory<T> factory) { |
| super(conf, uri, xface, factory); |
| this.proxies = getProxyAddresses(uri, |
| HdfsClientConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY); |
| } |
| |
| /** |
| * Lazily initialize the RPC proxy object. |
| */ |
| @Override |
| public synchronized ProxyInfo<T> getProxy() { |
| NNProxyInfo<T> current = proxies.get(currentProxyIndex); |
| return createProxyIfNeeded(current); |
| } |
| |
| @Override |
| public void performFailover(T currentProxy) { |
| incrementProxyIndex(); |
| } |
| |
| synchronized void incrementProxyIndex() { |
| currentProxyIndex = (currentProxyIndex + 1) % proxies.size(); |
| } |
| |
| /** |
| * Close all the proxy objects which have been opened over the lifetime of |
| * this proxy provider. |
| */ |
| @Override |
| public synchronized void close() throws IOException { |
| for (ProxyInfo<T> proxy : proxies) { |
| if (proxy.proxy != null) { |
| if (proxy.proxy instanceof Closeable) { |
| ((Closeable)proxy.proxy).close(); |
| } else { |
| RPC.stopProxy(proxy.proxy); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Logical URI is required for this failover proxy provider. |
| */ |
| @Override |
| public boolean useLogicalURI() { |
| return true; |
| } |
| } |